U.S. patent number 7,722,178 [Application Number 11/692,403] was granted by the patent office on 2010-05-25 for ink-jet head.
This patent grant is currently assigned to Brother Kogyo Kabushiki Kaisha. Invention is credited to Tadanobu Chikamoto, Yoshirou Kita, Hiroshi Taira.
United States Patent |
7,722,178 |
Taira , et al. |
May 25, 2010 |
Ink-jet head
Abstract
The passage unit is provided with a through hole that connects
the ink ejection face and the support face. The ink supply block is
provided with a through hole that connects the bond face and the
ink inlet face. The filter film blocks communication between the
through hole provided in the passage unit and the through hole
provided in the ink supply block.
Inventors: |
Taira; Hiroshi (Ichinomiya,
JP), Kita; Yoshirou (Nagoya, JP),
Chikamoto; Tadanobu (Nagoya, JP) |
Assignee: |
Brother Kogyo Kabushiki Kaisha
(Nagoya-shi, Aichi-ken, JP)
|
Family
ID: |
38558277 |
Appl.
No.: |
11/692,403 |
Filed: |
March 28, 2007 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070229635 A1 |
Oct 4, 2007 |
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Foreign Application Priority Data
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Mar 31, 2006 [JP] |
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2006-100628 |
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Current U.S.
Class: |
347/93;
347/71 |
Current CPC
Class: |
B41J
2/14024 (20130101); B41J 2202/11 (20130101); B41J
2002/14225 (20130101); B41J 2002/14217 (20130101) |
Current International
Class: |
B41J
2/175 (20060101); B41J 2/045 (20060101) |
Field of
Search: |
;347/68-72,93 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Meier; Stephen D
Assistant Examiner: Mruk; Geoffrey
Attorney, Agent or Firm: Baker Botts L.L.P.
Claims
What is claimed is:
1. An ink-jet head comprising: a passage unit that is made up of a
plurality of plate members laminated with each other, and includes
a plurality of individual ink passages each including a pressure
chamber and extending to an ink ejection port from which ink is
ejected, an ink ejection face formed with a plurality of the ink
ejection ports, and a support face formed with an inflow opening
through which ink flows in and facing in a direction opposite to a
facing direction of the ink ejection face; a filter film that is
attached to the support face so as to cover the inflow opening, to
thereby filter ink that passes through the inflow opening; a
piezoelectric actuator that is attached to the support face and
applies ejection energy to ink contained in the pressure chambers;
a wire member formed with a plurality of wires that are
electrically connected to the piezoelectric actuator and supply an
ejection signal to the piezoelectric actuator; and an ink supply
block that is made up of a plurality of plate members laminated
with each other, and includes a bond face and an ink inlet face,
the bond face being formed with an outflow opening through which
ink flows out and being bonded to the filter film in such a manner
that the inflow opening and the outflow opening are connected
through the filter film, the ink inlet face being formed with an
inlet hole into which ink is injected and facing in a direction
opposite to a facing direction of the bond face, wherein: the
passage unit is provided with a through hole that extends in a
direction perpendicular to the ink ejection face to connect the ink
ejection face and the support face; the ink supply block is
provided with a through hole that extends in the direction
perpendicular to the ink ejection face to connect the bond face and
the ink inlet face; and the filter film blocks communication
between the through hole provided in the passage unit and the
through hole provided in the ink supply block.
2. The ink-jet head according to claim 1, wherein a portion of the
filter film not opposed to the inflow opening covers at least
either one of the through hole provided in the passage unit and the
through hole provided in the ink supply block.
3. The ink-jet head according to claim 2, wherein: the filter film
has a filter region that is opposed to the inflow opening and in
which many holes are formed; and a portion of the filter film other
than the filter region covers at least either one of the through
hole provided in the passage unit and the through hole provided in
the ink supply block.
4. The ink-jet head according to claim 1, wherein the through hole
provided in the passage unit and the through hole provided in the
ink supply block are at different positions in a plan view.
5. The ink-jet head according to claim 1, wherein: the passage unit
and the ink supply block have elongated shapes in a plan view; one
or more through holes are provided at each longitudinal end portion
of the passage unit in a plan view; one or more through holes are
provided at each longitudinal end portion of the ink supply block
in a plan view; and the piezoelectric actuator is disposed on the
support face, in such a manner that the piezoelectric actuator
locates in a region corresponding to a space between, among the one
or more through holes provided at one longitudinal end portion of
the passage unit and at one longitudinal end portion of the ink
supply block, the through hole most distant from the one
longitudinal end and, among the one or more through holes provided
at the other end portions, the through hole most distant from the
other end.
6. The ink-jet head according to claim 5, comprising a plurality of
the piezoelectric actuators, wherein: the plurality of the
piezoelectric actuators are arranged in the longitudinal direction
in such a manner that piezoelectric actuators neighboring each
other in the longitudinal direction have their longitudinal end
portions overlap each other within the support face with respect to
the longitudinal direction; and the filter film is attached between
an end of the passage unit with respect to the longitudinal
direction and the piezoelectric actuator closest to the end.
7. The ink-jet head according to claim 6, wherein: a plurality of
the through holes are provided at each of the both longitudinal end
portions of the passage unit; and the filter film covers, among the
plurality of the through holes provided at the longitudinal end
portion of the passage unit, the through hole most distant from the
end.
8. The ink-jet head according to claim 7, wherein, in a plan view,
the through hole provided in the ink supply block locates on the
side opposite to the longitudinal end with respect to the through
hole that is provided at the longitudinal end portion of the
passage unit and besides covered with the filter film.
9. The ink-jet head according to claim 7, wherein, in a plan view,
the filter film extends to both widthwise end portions of the
passage unit.
10. The ink-jet head according to claim 1, wherein the ink supply
block further includes an opposing face that faces in the same
direction as a facing direction of the bond face while being spaced
apart from the support face, in such a manner that the opposing
face is opposed to the piezoelectric actuator with respect to a
direction perpendicular to the ink ejection face.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Japanese Patent Application
No. 2006-100628, filed Mar. 31, 2006, the disclosure of which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink-jet head that ejects ink to
a recording medium.
2. Description of Related Art
Some of ink-jet heads, which eject ink from nozzles to papers,
include a passage unit and an ink supply block. Formed in the
passage unit are individual ink passages each extending from a
manifold channel through a pressure chamber to a nozzle formed on a
lower face of the passage unit. The ink supply block supplies ink
to a manifold channel of the passage unit. Each of the passage unit
and the ink supply block has a layered structure of plates, and
they are bonded to each other in a layered direction. An actuator
unit is disposed on an upper face of the passage unit. A wire
member that supplies a signal to the actuator unit extends through
between the upper face of the passage unit and a lower face of the
ink supply block, upward along a side face of the ink supply block.
A volume of a pressure chamber included in an individual ink
passage is selectively changed by means of the actuator unit, so
that ejection energy is given to ink contained in the pressure
chamber. Ink is accordingly ejected from a nozzle that communicates
with this pressure chamber, and thus a desired image is printed on
a paper.
Japanese Patent Unexamined Publication No. 2005-22183 discloses an
ink-jet head in which positioning holes used in lamination of
plates are formed in respective plates that constitute a passage
unit and an ink supply block. These holes form through holes that
extend through the passage unit and the ink supply block from their
lower faces to upper faces.
SUMMARY OF THE INVENTION
In the ink-jet head disclosed in the above document, however, ink
adhering to the lower face of the passage unit on which nozzles are
formed may go through the through holes to the upper face of the
passage unit and then further go from the lower face of the ink
supply block through the through holes to the upper face of the ink
supply block. As a result, ink may adhere to a wire member placed
on a side face of the ink supply block, or ink may flow along the
wire member and adhere to an actuator unit. This may cause
electrical failure.
An object of the present invention is to provide an ink-jet head
that can suppress occurrence of electrical failure.
According to an aspect of the present invention, there is provided
an ink-jet head comprising a passage unit, a filter film, a
piezoelectric actuator, a wire member, and an ink supply block. The
passage unit is made up of a plurality of plate members laminated
with each other, and includes a plurality of individual ink
passages each including a pressure chamber and extending to an ink
ejection port from which ink is ejected, an ink ejection face
formed with a plurality of the ink ejection ports, and a support
face formed with an inflow opening through which ink flows in and
facing in a direction opposite to a facing direction of the ink
ejection face. The filter film is attached to the support face so
as to cover the inflow opening, to thereby filter ink that passes
through the inflow opening. The piezoelectric actuator is attached
to the support face and applies ejection energy to ink contained in
the pressure chambers. The wire member is formed with a plurality
of wires that are electrically connected to the piezoelectric
actuator and supply an ejection signal to the piezoelectric
actuator. The ink supply block is made up of a plurality of plate
members laminated with each other, and includes a bond face and an
ink inlet face. The bond face is formed with an outflow opening
through which ink flows out, and bonded to the filter film in such
a manner that the inflow opening and the outflow opening are
connected through the filter film. The ink inlet face is formed
with an inlet hole into which ink is injected, and faces in a
direction opposite to a facing direction of the bond face. The
passage unit is provided with a through hole that extends in a
direction perpendicular to the ink ejection face to connect the ink
ejection face and the support face. The ink supply block is
provided with a through hole that extends in the direction
perpendicular to the ink ejection face to connect the bond face and
the ink inlet face. The filter film blocks communication between
the through hole provided in the passage unit and the through hole
provided in the ink supply block.
In the above aspect, ink cannot go from the ink ejection face to
the ink inlet face through the through holes provided in the
passage unit and the ink supply block. This can prevent ink from
adhering to the piezoelectric actuator and the wire member.
Consequently, occurrence of electrical failure can be
suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS
Other and further objects, features and advantages of the invention
will appear more fully from the following description taken in
connection with the accompanying drawings in which:
FIG. 1 is a perspective view showing appearance of an ink-jet head
according to an embodiment of the present invention;
FIG. 2 is a sectional view of a reservoir unit shown in FIG. 1;
FIG. 3A is a top plan view of an ink introduction block shown in
FIG. 2;
FIG. 3B is a bottom plan view of the ink introduction block shown
in FIG. 2;
FIG. 3C is a top plan view of an uppermost plate that constitutes
an ink supply block shown in FIG. 2;
FIG. 3D is a top plan view of an intermediate plate that
constitutes the ink supply block shown in FIG. 2;
FIG. 3E is a bottom plan view of an lowermost plate that
constitutes the ink supply block shown in FIG. 2;
FIG. 4 is a perspective view of the ink introduction block shown in
FIG. 2, as seen at an angle from below;
FIG. 5 is a perspective view of the ink introduction block shown in
FIG. 2, as seen at an angle from above;
FIG. 6 is a plan view of a head main body shown in FIG. 1;
FIG. 7 is an exploded perspective view of the head main body shown
in FIG. 6;
FIG. 8 shows a partial cross section as taken along line VIII-VIII
in FIG. 6;
FIG. 9 shows on an enlarged scale a region enclosed by an alternate
long and short dash line in FIG. 6;
FIG. 10 shows a partial cross section as taken along line X-X in
FIG. 9;
FIG. 11 shows a part of a filter film shown in FIG. 6, on an
enlarged scale;
FIG. 12A shows a cross section of an actuator unit shown in FIG. 6,
on an enlarged scale;
FIG. 12B is a plan view of an individual electrode that is disposed
on a surface of the actuator unit in FIG. 12A;
FIG. 13A is a view for explaining a step of laminating an ink
supply block during a manufacturing process of the ink-jet head
shown in FIG. 1;
FIG. 13B is a view for explaining a step of laminating a passage
unit during the manufacturing process of the ink-jet head shown in
FIG. 1; and
FIG. 13C is a view for explaining a step of laminating the passage
unit and the ink supply block during the manufacturing process of
the ink-jet head shown in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following, a certain preferred embodiment of the present
invention will be described with reference to the accompanying
drawings.
FIG. 1 is a perspective view showing appearance of an ink-jet head
according to an embodiment of the present invention. As shown in
FIG. 1, an ink-jet head 1 having a shape elongated in a main
scanning direction includes, from a lower side in FIG. 1, a head
main body 2, a reservoir unit 3, and a substrate 4. The head main
body 2 is opposed to a paper. The reservoir unit 3 temporarily
stores ink therein, and supplies ink to a later-described passage
unit 9 (see FIG. 6) included in the head main body 2. The substrate
4 is mounted with connectors 5a and electronic components such as
capacitors 5b. In the present description, a side of the ink-jet
head 1 provided with the head main body 2 is defined as a lower
side, and a side thereof provided with the substrate 4 is defined
as an upper side.
Four actuator units 21 (see FIG. 6) are fixed onto an upper face of
the head main body 2, as will be detailed later. An FPC (Flexible
Printed Circuit) 6 acting as a wire member is attached onto each of
the actuator units 21. The FPC 6 extends through the head main body
2 and the reservoir unit 3, upward along a side face of the
reservoir unit 3. Thus, the FPC 6 has one end thereof connected to
the actuator unit 21, and the other end thereof connected to a
connector 5a of the substrate 4. In addition, a driver IC 7 is
mounted on the FPC 6 midway between the actuator unit 21 and the
substrate 4. That is, the FPC 6 is electrically connected to the
substrate 4 and the driver IC 7, so that an image signal outputted
from the substrate 4 is transmitted to the driver IC 7 and a drive
signal outputted from the driver IC 7 is supplied to the actuator
unit 21.
FIG. 2 is a sectional view of the reservoir unit 3 shown in FIG. 1.
For the purpose of explanatory convenience, FIG. 2 is drawn to an
enlarged scale in the vertical direction. FIGS. 3A to 3E are
exploded plan views of the reservoir unit 3 shown in FIG. 1. Here,
both FIGS. 3A and 3B show an ink introduction block 11 that
constitute a part of the reservoir unit 3. FIG. 3A is a top plan
view and FIG. 3B is a bottom plan view. FIGS. 3C and 3D are top
views of plates 12 and 13, respectively, that constitute a part of
the reservoir unit 3. FIG. 3E is a bottom view of a plate 14 that
constitutes a part of the reservoir unit 3. FIG. 4 is a perspective
view of the ink introduction block 11 shown in FIG. 2, as seen at
an angle from below. FIG. 5 is a perspective view of the ink
introduction block 11 shown in FIG. 2, as seen at an angle from
above. In order to make a structure of the ink introduction block
11 easy to understand, illustrations of a film 41, a film 42, and a
filter 37 which will de described later are omitted from FIGS. 3A
to 5.
As shown in FIGS. 3A to 3E, the reservoir unit 3 has a layered
structure laminated with an ink introduction block 11 and three
plates 12 to 14. The ink introduction block 11 is elongated in the
main scanning direction. Each of the three plates 12 to 14 has a
rectangular plane elongated in the main scanning direction. As
shown in FIG. 2, the plates 12 to 14 as laminated with each other
serve as an ink supply block 15. Here, the plates 12 to 14 are
metal plates made for example of a stainless steel or the like.
The uppermost ink introduction block 11 is made of a synthetic
resin such as a polyacetal resin and a polypropylene resin for
example. As shown in FIG. 2, an upper reservoir passage 34 is
formed inside the ink introduction block 11. The upper reservoir
passage 34 makes communication between an inlet 31 and an outlet
33. The inlet 31 is provided on an upper face 11a of the ink
introduction block 11, near one longitudinal end portion thereof,
i.e., a left end portion in FIG. 2. The outlet 33 is provided on a
lower face 11b of the ink introduction block 11, at a longitudinal
center thereof. Thus, the upper reservoir passage 34 is formed only
in a portion of the ink introduction block 11 between the center
and the one end with respect to an extending direction of the ink
introduction block 11. A tubular joint 30 is formed on the upper
face 11a of the ink introduction block 11. The tubular joint 30
surrounds the inlet 31 and protrudes upward. A connection member is
connected to the joint 30. The connection member is coupled to an
end of a not-shown ink supply tube that is connected to a not-shown
ink tank. Thus, ink is supplied from the ink tank through the joint
30 to the upper reservoir passage 34.
As shown in FIGS. 3A and 5, an elliptical opening 32 is formed on
the upper face 11a of the ink introduction block 11. The opening 32
is elongated along a longitudinal direction of the ink introduction
block 11. The opening 32 is formed in a region of the upper face
11a opposed to where the upper reservoir passage 34 is formed. One
longitudinal end, which means a right end in FIGS. 2 and 3A, of the
opening 32 is opposed to the outlet 33 that is formed on the lower
face 11b. As shown in FIG. 2, the opening 32 is sealed with the
film 42. Further, as shown in FIGS. 3B and 4, an opening 35
extending in the main scanning direction is formed on the lower
face 11b of the ink introduction block 11. The opening 35 is formed
in a region stretching from a portion opposed to the inlet 31 that
is formed on the upper face 11a to a portion opposed to a vicinity
of the other end of the opening 32 that is formed on the upper face
11a. The other end of the opening 32 is opposite to the one end
thereof opposed to the outlet 33. As shown in FIG. 2, the opening
35 is sealed with the film 41.
Like this, due to the film 41 that seals the opening 35 and the
film 42 that seals the opening 32, the ink introduction block 11 is
formed with the upper reservoir passage 32 extending from the inlet
31 that locates at the one longitudinal end portion of the ink
introduction block 11 to the outlet 33 that locates at the
longitudinal center of the ink introduction block 11. As shown in
FIG. 2, in a region of the upper reservoir passage 34 existing
between a substantially central portion with respect to an
extending direction of the upper reservoir 34 and a portion at
which ends of the respective openings 35 and 32 are opposed to each
other, a depth of the upper reservoir passage 34, which means a
length of the upper reservoir passage 34 with respect to an
up-and-down direction in FIG. 2, is expanded upward. A filter 37 is
provided in this deeper region. In this way, ink supplied from the
ink tank flows through the inlet 31 into the upper reservoir
passage 34, passes through the filter 37, and then flows out
through the outlet 33.
Here, the films 41 and 42 that seal the openings 35 and 32,
respectively, are made of a flexible material having an excellent
gas barrier property, such as a PET (polyethylene terephthalate)
film that is vapor-deposited with a silica film (SiOx film) or an
aluminum film. Accordingly, air existing outside the ink-jet head 1
can hardly go through the films 41 and 42 into the upper reservoir
passage 34 of the ink introduction block 11.
On the lower face 11b of the ink supply block 11, an annular groove
43 is formed around the outlet 33. An O-ring 44 is fitted in the
annular groove 43, so that the outlet 33 and an inlet hole 53 are
in water-tight communication with each other. As will be described
later, the inlet hole 53 is formed in the plate 12. As shown in
FIGS. 3A and 3B, four through holes 45 to 48 are formed through the
ink introduction block 11 from the upper face 11a to the lower face
11b. The through holes 45 to 48 are for screwing the ink
introduction block 11 to the plate 12.
As shown in FIGS. 3A and 5, two hooks 26 protruding upward are
formed at each end of the ink introduction block 11 with respect to
the sub scanning direction. The hooks 26 are formed on an outer
peripheral side face of the ink introduction block 11. The hooks 26
are for holding and maintaining an upper face of the substrate 4
which will be disposed on the ink introduction block 11.
As shown in FIGS. 2 and 3C, through holes 51 are formed at both
longitudinal end portions, with respect to the sub scanning
direction, of the uppermost plate 12 of the ink supply block 15.
The through holes 51 are used for fixing the ink-jet head 1 to a
printer main body by means of screws. The plate 12 also has, at its
center, a through hole that is connected to the inlet hole 53
formed on the upper face of the plate 12. The plate 12 further has
reference holes 54 at its portions a little closer to the center
than the through holes 51 are. The reference holes 54 are used for
positioning the plates when assembling the plates. The plate 12
further has four screw holes 56 to 59. The four screw holes 56 to
59 correspond to the four through holes 45 to 48 of the ink
introduction block 11 described above. By screwing the ink
introduction block 11 and the plate 12 to each other, the outlet 33
of the ink introduction block 11 and the inlet hole 53 of the plate
12 get opposed to each other, to make communication between the
upper reservoir passage 34 and the through hole of the plate 12
connected to the inlet hole 53.
As shown in FIGS. 2 and 3D, the intermediate plate 13 of the ink
supply block 15 has a through hole that serves as a lower reservoir
passage 86. The lower reservoir passage 86 includes a main passage
82 and ten branch passages 83 communicating with the main passage
82. The main passage 82 has a substantially elliptical shape
elongated in a longitudinal direction of the plate 13. A center of
the main passage 82 is opposed to the inlet hole 53 of the plate
12. A passage width of the branch passage 83 is smaller than a
passage width of the main passage 82. Any of the branch passages 83
extends from a longitudinal end of the main passage 82 to a
widthwise end portion of the plate 13. The plate 13 further has
reference holes 64 each corresponding to each of the respective
reference holes 54 of the plate 12, and relief holes 61 each
locating between each reference hole 64 and each longitudinal end
of the plate 13. The relief holes 61 are used in assembling the
passage unit 9 and the ink supply block 15 to each other. In such
an assembly step, an insertion pin 99 standing on a stationary
assembly plate (see FIG. 13C) makes positioning as will be
described later. At this time, a distal end of the insertion pin 99
locates within the relief hole 61.
As shown in FIG. 3E, the lowermost plate 14 of the ink supply block
15 has through holes that are connected to respective outflow
openings 88. The outflow openings 88, each of which has a
substantially elliptical shape in a plan view, are formed on a
lower face of the plate 14 at positions opposed to ends of the
respective branch passages 83. That is, every outflow opening 88 is
formed at widthwise end portion of the plate 14. Portions of the
lower face of the plate 14 surrounding the outflow openings 88
protrude, and form protrusions 89a, 89b, 89c, and 89d. In this
embodiment, the protrusions 89a to 89d of the plate 14, as well as
the through holes connected to the outflow openings 88, are formed
by an etching process. Bond faces 90a to 90d of the protrusions 89a
to 89d, which are the lower face of the plate 14, are fixed to
filter films 95a and 95b that are disposed on a support face 9a,
i.e., an upper face, of the passage unit 9, as will be described
later. Consequently, a portion of the lower face of the plate 14
except the bond faces 90a to 90d is an opposing face 15b that is
spaced apart from the support face 9a of the passage unit 9. Thus,
a predetermined space is formed between the opposing face 15b and
the support face 9a. The above-described FPC 6 extends through this
space. In addition, the plate 14 has positioning holes 71 and
reference holes 74 that correspond to the relief holes 61 and the
reference holes 64 formed in the plate 13, respectively.
By inserting insertion pins 97 (see FIG. 13A) into the two
reference holes 54, the two reference holes 64, and the two
reference holes 74, which are formed in the plates 12, 13, and 14,
respectively, the three plates 12 to 14 are positioned with one
another. At this time, as shown in FIG. 2, the relief holes 61
formed in the plate 13 communicate with the positioning holes 71
formed in the plate 14. Here, all the reference holes 54, 64, and
74 formed in the respective plates 12 to 14 have the same diameter.
A diameter of the relief hole 61 is larger than a diameter of the
positioning hole 71 that corresponds to the relief hole 61. The
plates 12 to 14 are fixed to each other with an adhesive, thus
forming the ink supply block 15. As shown in FIG. 2, due to the
reference holes 54, 64, and 74 formed in the respective plates 12
to 14, through holes 84 appear in the ink supply block 15. The
through holes 84 extend in a direction of lamination of the plates
12 to 14, from the bond faces 90a and 90d which are the lower face
of the ink supply block 15 to an ink inlet face 15a which is an
upper face of the ink supply block 15. Further, by screwing the ink
introduction block 11 and the ink supply block 15 to each other, to
form the reservoir unit 3.
Next, a description will be given to how ink flows within the
reservoir unit 3 when ink is supplied. In FIG. 2, black arrows
indicate a flow of ink within the reservoir unit 3.
Ink having flown from the not-shown ink tank into the joint 30 as
described above passes through the inlet 31, the upper reservoir
passage 34, and the outlet 33 of the ink introduction block 11, and
then flows through the inlet hole 53 of the plate 12 into the lower
reservoir passage 86 of the plate 13. That is, ink is filtered
through the filter 37 provided in the upper reservoir passage 34,
and then flows into the lower reservoir passage 86. In the main
passage 82 of the lower reservoir passage 86, ink makes stream
toward both longitudinal ends of the reservoir unit 3. At both ends
of the main passage 82, ink branches into the respective branch
passages 83 and flows to the outflow openings 88 of the plate 14.
The outflow openings 88 are in communication with inflow openings
101 that are formed in the passage unit 9 as will be described
later, so that ink is supplied into the passage unit 9.
Like this, a series of ink passages such as the upper reservoir
passage 34 and the lower reservoir passage 86 is formed in the
reservoir unit 3, and acts as an ink reservoir that temporarily
stores ink therein.
Next, the head main body 2 will be described with reference to
FIGS. 6 to 12B. FIG. 6 is a plan view of the head main body 2. FIG.
7 is an exploded perspective view of the head main body 2 shown in
FIG. 6. FIG. 8 shows a partial cross section as taken along line
VIII-VIII in FIG. 6. FIG. 9 shows on an enlarged scale a region
enclosed by an alternate long and short dash line in FIG. 6. In
FIG. 9, for the purpose of explanatory convenience, pressure
chambers 110, apertures 112, and nozzles 108 are illustrated with
solid lines although they locate below the actuator units 21 and
therefore should actually be illustrated with broken lines. FIG. 10
shows a partial cross section as taken along line X-X in FIG. 9.
FIG. 11 shows on an enlarged scale a part of a filter film shown in
FIG. 6. FIG. 12A shows a cross section of the actuator unit 21 on
an enlarged scale. FIG. 12B is a plan view of an individual
electrode that is disposed on a surface of the actuator unit 21 in
FIG. 12A.
As shown in FIG. 6, the head main body 2 includes the passage unit
9, four actuator units 21, and filter films 95a and 95b. The four
actuator units 21, and filter films 95a and 95b are fixed to the
support face 9a of the passage unit 9.
The passage unit 9 has a rectangular parallelepiped shape that is,
in a plan view, substantially the same as a shape of the plate 14
of the reservoir unit 3. As described above, a total of ten inflow
openings 101 communicating with the outflow openings 88 of the ink
supply block 15 are formed on the support face 9a of the passage
unit 9. As shown in FIG. 6, five of the inflow openings 101 are
formed at each widthwise end portion of the passage unit 9. To be
more specific, at each widthwise end portion, two pairs of adjacent
inflow openings 101 and one isolated inflow opening 101 are
disposed at substantially regular intervals along a longitudinal
direction of the passage unit 9. The pairs of inflow openings 101
and the isolated inflow openings 101, which are disposed at both
widthwise end portions, are not opposed to one another with respect
to a widthwise direction of the passage unit 9. The isolated inflow
opening 101 formed at one widthwise end portion, i.e., at a lower
end portion in FIG. 6, is situated at one longitudinal end portion,
i.e., at a right end portion in FIG. 6, and the isolated inflow
opening 101 formed at the other widthwise end portion, i.e., at an
upper end portion in FIG. 6, is situated at the other longitudinal
end portion, i.e., at a let end portion in FIG. 6.
An ink ejection face 9b which means a lower face of the passage
unit 9 provides, in its region opposed to where each actuator unit
21 is bonded, an ink ejection region in which many nozzles 108 are
arranged in a matrix as shown in FIG. 9. The ink ejection face 9b
is perpendicular to a direction of lamination of the reservoir unit
3 and the passage unit 9. As shown in FIGS. 6 and 9, manifold
channels 114 and sub manifold channels 114a are formed inside the
passage unit 9. The manifold channel 114 is a common ink chamber,
and communicates with the inflow opening 101. The sub manifold
channel 114a is a branch passage of the manifold channel 114.
Connected to the sub manifold channel 114a are individual ink
passages 132 each including a pressure chamber 110 and
communicating with each nozzle 108 (see FIG. 10). The individual
ink passages 132 are formed in a region opposed to where each
actuator unit 21 is bonded. Thus, ink flows from the inflow
openings 101 into the manifold channels 114, the sub manifold
channels 114a, and the individual ink passages 132.
In the region opposed to where each actuator unit 21 is bonded,
many pressure chambers 110 are arranged in a matrix. In this
embodiment, as shown in FIG. 9, sixteen pressure chamber rows, in
each of which pressure chambers 110 are arranged at regular
intervals in the longitudinal direction of the passage unit 9,
which means a horizontal direction in FIG. 9, are disposed in
parallel to each other with respect to the widthwise direction of
the passage unit 9, which means an up-and-down direction in FIG. 9.
The number of pressure chambers 110 included in each pressure
chamber row is, in conformity with an outer shape of the actuator
unit 21, which is a trapezoidal shape as will be described later,
gradually reduced from a longer side to a shorter side of the
actuator unit 21. Nozzles 108 are arranged in the same manner,
too.
As shown in FIGS. 7 and 10, the passage unit 9 is made up of nine
plates of, from the top, a cavity plate 122, a base plate 123, an
aperture plate 124, a supply plate 125, manifold plates 126, 127,
128, a cover plate 129, and a nozzle plate 130. Like the plates 12
to 14 of the reservoir unit 3, the respective plates 122 to 130 are
metal plates made of a stainless steel or the like. In this
embodiment, the plates 122 to 130 are made of SUS. Each of the
plates 122 to 130 has a rectangular plane elongated in the main
scanning direction.
Formed in the cavity plate 122 are many substantially rhombic
through holes serving as pressure chambers 110. Formed in the
aperture plate 124 are through holes serving as apertures 112. The
apertures function as throttles, and communicate with the
respective pressure chambers 110 through connection holes formed in
the base plate 123. Formed in the manifold plates 126, 127, and 128
are through holes that are, when the plates are in layers, combined
with each other to form manifold channels 114 and sub manifold
channels 114a. The manifold channels 114 communicate with the
inflow openings 101 formed on the support face 9a, through
connection holes formed in the plates 122 to 125. The sub manifold
channels 114a communicate with the apertures 112 through connection
holes formed in the supply plate 125. Formed in the nozzle plate
130 are holes serving as nozzles 108. The nozzles 108 communicate
with the respective pressure chambers 110 through connection holes
formed in the plates 123 to 129.
The nine plates 122 to 130 are positioned, laminated, and fixed to
one another so as to form, within the passage unit 9, individual
ink passages 132 each extending from an outlet of a sub manifold
channel 114a through an aperture 112 and a pressure chamber 110 to
a nozzle 108 as shown in FIG. 10. Positioning of the respective
plates 122 to 130 is performed using lamination check holes 122a to
130a and reference holes 122b to 130b (see FIG. 7), which will be
detailed later.
As shown in FIG. 7, three kinds of holes, which mean the lamination
check holes 122a to 130a, the reference holes 122b to 130b, and the
positioning holes 122c to 130c are formed at both longitudinal end
portions of the respective plates 122 to 130. The three kinds of
holes 122a to 130a, 122b to 130b, and 122c to 130c are arranged
along a longitudinal direction of the respective plates 122 to 130.
When the plates 122 to 130 are in layers, the three kinds of holes
122a to 130a, 122b to 130b, and 122c to 130c respectively form
three through holes 102, 104, and 106 at both longitudinal end
portions of the passage unit 9 (see FIG. 6). The three through
holes 102, 104, and 106 align along the longitudinal direction of
the passage unit 9.
As shown in FIG. 8, any of the three through holes 102, 104, and
106 extends through the passage unit 9, from the upper face or the
support face 9a to the lower face or the ink ejection face 9b.
Among the three through holes 102, 104, and 106, the middle through
hole 104 is made up of the reference holes 122b to 130b that are
formed in the plates 122 to 130. The reference holes 122b to 130b
are used for positioning the plates 122 to 130 in assembling the
passage unit 9. That is, all of the reference holes 122b to 130b
have the same diameter, and an insertion pin 98 (see FIG. 13B) is
inserted through the reference holes 122b to 130b. The plates 122
to 130 are fixed to each other with an adhesive, to form the
passage unit 9. By positioning and laminating the plates 122 to 130
with each other using these reference holes 122b to 130b, the other
two through holes 102 and 106 are formed.
Among the three through holes 102, 104, and 106, through hole 106
closest to a longitudinal center of the passage unit 9 is made up
of the lamination check holes 122a to 130a that are formed in the
plates 122 to 130. As shown in FIG. 8, among the lamination check
holes 122a to 130a, the one formed in the cavity plate 122 which is
the uppermost plate in the passage unit 9 has the smallest
diameter. The lower plate a lamination check hole is formed in, the
larger diameter the lamination check hole has. The lamination check
hole formed in the nozzle plate 130 which is the lowermost plate
has the largest diameter. The lamination check holes 122a to 130a
are used in laminating the plates 122 to 130, for making a fine
adjustment after rough positioning is made using the reference
holes 122b to 130b. As a result of the fine adjustment, the
lamination check holes 122a to 130a that will form the through hole
106 are positioned substantially coaxially.
Among the three through holes 102, 104, and 106, the through hole
102 placed opposite to the through hole 106 across the middle
through hole 104 is made up of the positioning holes 122c to 130c
that are formed in the plates 122 to 130. The through hole 102 is
used for positioning the passage unit 9 and the ink supply block 15
with each other. All the positioning holes 122c to 130c have the
same diameter. The through hole 102 is formed at a position
corresponding to the relief hole 61 and the positioning hole 71 of
the plates 13 and 14 of the ink supply block 15, respectively. The
through hole 102 has the same diameter as that of the positioning
hole 71. By inserting an insertion pin 99 (see FIG. 13C) through
the relief hole 61, the positioning hole 71, and the through hole
102, the passage unit 9 and the ink supply block 15 are positioned
with each other.
As described above, the three through holes 102, 104, and 106 are
formed at the both longitudinal end portions of the passage unit 9.
Therefore, for laminating the plates 122 to 130 which will
constitute the passage unit 9, the insertion pins 98 are inserted
through the two through holes 104. For assembling the passage unit
9 and the ink supply block 15 to each other, the insertion pins 99
are inserted through the two through holes 102 and two positioning
holes 71 that correspond to the two through holes 102.
Filter films 95a and 95b that covers the inflow openings 101 are
disposed on the support face 9a of the passage unit 9. As shown in
FIG. 11, many filter holes 96a are formed in a region of the filter
films 95a and 95b opposed to the inflow opening 101, to thereby
provide a filter region 96 capable of filtering ink which will be
supplied through the inflow openings 101 into the passage unit 9.
The filter holes 96a are not formed in a region not opposed to the
inflow opening 101.
As shown in FIG. 6, the filter film 95a covers the isolated inflow
opening 101 that is situated at each longitudinal end portion of
the passage unit 9. The filter film 95a is disposed between a
longitudinal end of the passage unit 9 and, among the four actuator
units 21 fixed to the support face 9a, the actuator unit 21 closest
to this longitudinal end. The filter film 95a slants across a width
of the passage unit 9, and extends up to the both widthwise end
portions of the passage unit 9. A region of the filter film 95a
other than the filter region 96 covers the through hole 106
positioned closest to the longitudinal center of the passage unit
9. The through holes 102 and 104 are not covered with the filter
film 95a. However, even if ink adhering to the ink ejection face 9b
comes up to the support face 9a through the through holes 102 and
104, the ink cannot reach a region where the actuator units 21
exist because the filter film 95a is extending up to the both
widthwise end portions on the support face 9a. The filter films 95b
extend along the longitudinal direction of the passage unit 9, and
cover four pairs of adjacent inflow openings 101.
That is, the total number of the filter plates 95a and 95b is six.
As illustrated with alternate long and two short dashes lines in
FIG. 6, the filter plates 95a and 95b are disposed in regions
opposed to the respective protrusions 89a to 89d that are formed on
the plate 14 of the reservoir unit 3. The filter films 95a and 95b
are bonded with adhesive to the bond faces 90a to 90d of the
protrusions 89a to 89d. When bonded to the bond faces 90a and 90d,
the filter films 95a cover lower openings of the through holes 84
that are formed in the ink supply block 15 (see FIG. 13C).
As described above, each of the actuator units 21 is disposed in
opposition to the region where pressure chambers 110 and nozzles
108 are formed. The actuator unit 21 includes actuators each
opposed to each pressure chamber 110, and has a function of giving
ejection energy to ink contained within the pressure chambers
110.
As shown in FIG. 6, in a region of the support face 9a between the
filter films 95a disposed at the both longitudinal end portions,
the four actuator units 21 each having a trapezoidal shape in a
plan view are arranged in a zigzag pattern so as to keep out from
the inflow openings 101. More specifically, the actuator units 21
are arranged in the longitudinal direction of the passage unit 9,
with parallel opposed sides of each actuator unit 21 extending
along the longitudinal direction. Oblique sides of every
neighboring actuator units 21 overlap each other with respect to
the widthwise direction of the passage unit 9.
Since each actuator unit 21 has a trapezoidal outer shape as
described above, regions causing no ink ejection appear at both
outermost end portions of a set of the four actuator units 21 with
respect to the main scanning direction. The regions causing no ink
ejection are nonprint regions situated outside a print region in
which printing on a recording medium is performed. Regions A shown
in FIG. 6 correspond to these regions. As shown in FIG. 6, the
print region where the respective actuators are disposed is
situated in a center, and the nonprint regions which are continuous
with the print region serve to separate regions where the through
holes 106 and the like are formed from the print region.
Consequently, the actuator units 21 are not easily affected by ink
intrusion.
As described above, the ink supply block 15 is, by means of the
protrusions 89a to 89d, fixed to the filter films 95a and 95b
disposed on the passage unit 9. Therefore, the opposing face 15b of
the ink supply block 15 and the support face 9a of the passage unit
9 are spaced apart at an interval corresponding to a protruding
height of the protrusions 89a to 89d and a thickness of the filter
films 95a and 95b. In this interval, the actuator units 21 are
disposed. The FPC 6, which is fixed on the actuator unit 21, is not
in contact with the opposing face 15b of the ink supply block 15
that is opposed to the FPC 6.
The actuator unit 21 is a unimorph type actuator, and as shown in
FIG. 12A made up of three piezoelectric sheets 141, 142, and 143
each having a thickness of approximately 15 .mu.m and made of a
lead zirconate titanate (PZT)-base ceramic material with
ferroelectricity. The piezoelectric sheets 141 to 143 are disposed
so as to extend over many pressure chambers 110 that are formed
corresponding to one ink ejection face.
On the uppermost piezoelectric sheet 141, individual electrodes 135
are formed at positions opposed to the respective pressure chambers
110. The individual electrode 135 has a thickness of approximately
1 .mu.m. A common electrode 134 having a thickness of approximately
2 .mu.m is interposed between the uppermost piezoelectric sheet 141
and the piezoelectric sheet 142 disposed under the uppermost
piezoelectric sheet 141. The common electrode 134 is formed over an
entire surface of the sheet. Both of the individual electrodes 135
and the common electrode 134 are made of a metal material such as
an Ag--Pd-base one for example. No electrode is disposed between
the piezoelectric sheets 142 and 143.
In a plan view, as shown in FIG. 12B, the individual electrode 135
has a substantially rhombic shape that is substantially the same as
a shape of the pressure chamber 110. As shown in FIGS. 12A and 12B,
one acute portion of the substantially rhombic individual electrode
135 extends out to a location not opposed to the pressure chamber
110, and a circular land 136 is provided on an end of this
extending-out portion. The land 136 has a diameter of approximately
160 .mu.m, and is electrically connected to the individual
electrode 135. The land 136 is made for example of gold including
glass frits. Each land 136 is electrically bonded to a contact,
i.e., a lead wire, provided on the FPC 6 (see FIG. 1).
In a region not illustrated, the common electrode 134 is grounded.
As a consequence, the common electrode 134 is, at its portions
corresponding to all the pressure chambers 110, equally kept at the
ground potential.
Here, a mode of driving the actuator unit 21 will be described. The
piezoelectric sheet 141 is polarized in its thickness direction.
When an individual electrode 135 is set at a potential different
from a potential of the common electrode 134, an electric field in
a polarization direction is applied to the piezoelectric sheet 141.
As a result, a portion of the piezoelectric sheet 141 to which the
electric field is applied acts as an active portion which is
distorted by a piezoelectric effect. That is, the piezoelectric
sheet 141 extends or contracts in its thickness direction, and
contracts or extends in a plane direction by a transversal
piezoelectric effect. The other two piezoelectric sheets 142 and
143 form inactive layers not including a region sandwiched between
an individual electrode 135 and the common electrode 134, and
therefore cannot deform by themselves.
When difference occurs between plane-direction distortion of a
portion of the piezoelectric sheet 141 to which the electric field
is applied and plane-direction distortion of the lower
piezoelectric sheets 142 and 143, the piezoelectric sheets 141 to
143 as a whole deform protrudingly toward a pressure chamber 110,
i.e. that is cause unimorph deformation. This reduces a volume of
the pressure chamber 110, so that ink is ejected from a nozzle 108.
Then, when the individual electrode 135 is set at the same
potential as the potential of the common electrode 134, the
piezoelectric sheets 141 to 143 restore the original flat shape,
and the volume of the pressure chamber 110 is also returned to the
original one. Ink is accordingly stored into the pressure chamber
110 again. In this way, a desired image is printed on a paper.
Next, a process of manufacturing the ink-jet head 1 will be
described with reference to FIGS. 13A to 13C.
In order to manufacture the ink supply block 15, first, three metal
plates are subjected to an etching process using a patterned
photoresist as a mask, to prepare the three plates 12 to 14 as
shown in FIGS. 3C to 3E. Then, as shown in FIG. 13A, the insertion
pin 97 is inserted through the reference holes 54, 64, and 74
formed in the respective plates 12 to 14, and in this condition the
three plates 12 to 14 are laminated and positioned with each other.
The reference holes 54, 64, and 74 have the same diameter.
Therefore, accurate positioning can be made by fitting therein the
insertion pin 97 adapted to interfit with the reference holes 54,
64, and 74. At this time, an epoxy-base thermosetting adhesive is
interposed between the respective plates 12 to 14. Then, the three
plates 12 to 14 are heated under pressure to not lower than a
curing temperature of the thermosetting adhesive. As a result, the
thermosetting adhesive is cured to bond the three plates 12 to 14
to each other, thus forming the ink supply block 15.
In order to manufacture the head main body 2, on the other hand,
nine metal plates are subjected to an etching process using a
patterned photoresist as a mask, to prepare the nine plates 122 to
130 as shown in FIG. 7. Then, as shown in FIG. 13B, the insertion
pin 98 is inserted through the reference holes 122b to 130b formed
in the respective plates 122 to 130, and in this condition the nine
plates 122 to 130 are laminated and positioned with each other. The
reference holes 122b to 130b formed in the respective plates 122 to
130 have the same diameter. Therefore, substantially accurate
positioning can be made by fitting therein the insertion pin 98
adapted to interfit with the reference holes 122b to 130b.
Further, highly accurate positioning of the plates 122 to 130 is
made using the lamination check holes 122a to 130a. More
specifically, when laminating the cover plate 129 on the lowermost
nozzle plate 130 for example, the lamination check hole 129a of the
cover plate 129 and the lamination check hole 130a of the nozzle
plate 130 are brought into axial alignment to thereby make highly
accurate positioning of the plates 129 and 130. At this time, an
epoxy-base thermosetting adhesive is interposed between the
respective plates 122 to 130. After laminated, the plates 122 to
130 are heated under pressure to not lower than a curing
temperature of the thermosetting adhesive. As a result, the nine
plates 122 to 130 are bonded to each other, thus forming the
passage unit 9. Then, the actuator unit 21 prepared in a separate
step and the filter films 95a and 95b are fixed to the support face
9a of the passage unit 9 with an adhesive, thus forming the head
main body 2.
Since a step of preparing the ink supply block 15 and a step of
preparing the head main body 2 are performed separately, either one
of them may precede the other or alternatively they may be
performed simultaneously.
Thereafter, the FPC 6 and the actuator unit 21 are electrically
connected to each other, and then the insertion pin 99 is inserted
through the through hole 102 formed in the passage unit 9 and the
positioning hole 71 formed in the plate 14 of the ink supply block
15, as shown in FIG. 13C. A distal end of the insertion pin 99
locates within the relief hole 61 formed in the plate 13 of the ink
supply block 15. At this time, the passage unit 9 and the ink
supply block 15 are positioned with each other in such a manner
that the inflow openings 101 of the passage unit 9 and the outflow
openings 88 of the ink supply block 15 are connected through the
filter films 95a and 95b. Here, through hole 102 and the
positioning hole 71 have the same diameter. Therefore, accurate
positioning can be made by fitting therein the insertion pin 99
adapted to interfit with the through hole 102 and the positioning
hole 71.
At this time, an epoxy-base thermosetting adhesive is interposed
between the bond faces 90a to 90d of the protrusions 89a to 89d of
the ink supply block 15 and regions of the filter films 95a and
95b, which are disposed on the support face 9a of the passage unit
9, other than the filter regions 96. Subsequently, the passage unit
9 and the ink supply block 15 are heated under pressure to not
lower than a curing temperature of the thermosetting adhesive. As a
result, the thermosetting adhesive is cured to bond the passage
unit 9 and the ink supply block 15 to each other through the filter
films 95a and 95b.
In this embodiment, in a state where the passage unit 9 and the ink
supply block 15 are positioned with each other, the through hole 84
formed in the ink supply block 15 is, in a plan view, at a position
different from positions of the through holes 102, 104, and 106
formed in the passage unit 9, as shown in FIG. 13C. To be more
specific, the through hole 102 of the passage unit 9, the through
hole 104 of the passage unit 9, the through hole 106 of the passage
unit 9, and the through hole 84 of the ink supply block 15 are
placed in this sequence starting from the longitudinal end of the
passage unit 9 and the ink supply block 15 toward a longitudinal
center thereof, i.e., from left to right in FIG. 13C. As described
above, among the through holes 102, 104, and 106 of the passage
unit 9, the through hole 106, which is the one most distant from
the longitudinal end of the passage unit 9, has its upper end
covered with the region of the filter film 95a other than the
filter region 96. Moreover, as shown in FIG. 13C, the through hole
84 of the ink supply block 15 has its lower end covered with the
region of the filter film 95a other than the filter region 96.
Further, the ink introduction block 11, which is separately
prepared through injection molding or the like and provided with
the films 41, 42 and the filter 37, is fixed to the ink supply
block 15 by screws, thus forming the reservoir unit 3. In addition,
the substrate 4 is engaged with the hooks 26 of the ink
introduction block 11, and thus fixed to the reservoir unit 3.
Finally, an end of the FPC 6 not connected to the actuator unit 21
is connected to the connector 5a of the substrate 4. In this way,
the ink-jet head 1 made up of the reservoir unit 3, the head main
body 2, and the substrate 4 is manufactured.
As thus far described above, the ink-jet head 1 of this embodiment
includes the passage unit 9, the filter films 95a, and the ink
supply block 15. The passage unit 9 has, on its upper face or the
support face 9a, the inflow openings 101 through which ink flows.
The filter films 95a are attached to the support face 9a so as to
cover the inflow openings 101 of the passage unit 9. The ink supply
block 15 has the inlet hole 53 into which ink is injected and the
outflow openings 88 from which ink flows out. The outflow openings
88 are connected to the inflow openings 101 of the passage unit 9
through the filter films 95a. The through holes 102, 104, and 106
are formed through the passage unit 9 from its lower face or the
ink ejection face 9b to the support face 9a. The through holes 84
are formed through the ink supply block 15, from its lower face or
the bond faces 90a to 90d connected to the filter films 95a, to its
upper face or the ink inlet face 15a. The filter films 95a inhibit
communication between the through holes 84 formed in the ink supply
block 15 and the through holes 102, 104, and 106 formed in the
passage unit 9. Accordingly, ink cannot go from the ink ejection
face 9b to the ink inlet face 15a through the through holes 102,
104, 106, and 84. This can prevent that ink having reached the ink
inlet face 15a adheres to the FPC 6 which extends upward along the
side face of the ink supply block 15, or ink having reached the ink
inlet face 15a flows along the FPC 6 and adhere to the actuator
unit 21. Consequently, electrical failure can be suppressed.
In the ink-jet head 1 of this embodiment, the lower openings of the
through holes 84 formed in the ink supply block 15 are covered with
the regions of the filter films 95a, which are disposed on the
support face 9a of the passage unit 9, other than the filter
regions 96 that are opposed to the inflow openings 101.
Accordingly, the filter films 95a block communication between the
through holes 102, 104, and 106 formed in the passage unit 9 and
the through hole 84 formed in the ink supply block 15. This can
surely prevent ink from going from the ink ejection face 9b to the
ink inlet face 15a through the through holes 102, 104, 106, and
84.
In the ink-jet head 1 of this embodiment, many filter holes 96a are
formed only in the region of the filter film 95a opposed to the
inflow opening 101. That is, the filter holes 96a are not formed in
a region of the filter film 95a covering the through hole 84.
Accordingly, the filter films 95a surely block communication
between the through holes 102, 104, and 106 formed in the passage
unit 9 and the through hole 84 formed in the ink supply block 15.
This can more surely prevent ink from going from the ink ejection
face 9b to the ink inlet face 15a through the through holes 102,
104, 106, and 84.
In the ink-jet head 1 of this embodiment, the through holes 84
formed in the ink supply block 15 are, in a plan view, at positions
different from positions of the through holes 102, 104, and 106
formed in the passage unit 9. This can still more surely prevent
ink from going from the ink ejection face 9b to the ink inlet face
15a through the through holes 102, 104, 106, and 84.
In the ink-jet head 1 of this embodiment, the passage unit 9 and
the ink supply block 15 have elongated shapes in a plan view, and
the through holes 102, 104, 106, and 84 are formed at the both
longitudinal end portions of the passage unit 9 and the ink supply
block 15. Accordingly, a relatively large actuator unit 21 can be
disposed between the through holes 102, 104, 106, and 84 which are
formed in the both longitudinal end portions of the passage unit 9
and the ink supply block 15. In addition, actuator units 21 each
having a trapezoidal shape are disposed concentratedly in the
vicinity of a longitudinal center, so that there are nonprint
regions between the actuator units 21 and the through holes 102,
104, and 106. Therefore, ink can hardly go from the ink ejection
face 9b into the through holes 102, 104, and 106.
In the ink-jet head 1 of this embodiment, the four actuator units
21 disposed on the support face 9a of the passage unit 9 are
arranged in the longitudinal direction, in such a manner that
actuator units 4 neighboring each other in the longitudinal
direction have their end portions with respect to the longitudinal
direction overlap each other with respect to the longitudinal
direction on the support face 9a. The filter film 95a is attached
between a longitudinal end of the passage unit 9 and the actuator
unit 21 closest to this longitudinal end. This can realize a
relatively long line without increasing a size of each actuator
unit 21.
In the ink-jet head 1 of this embodiment, the filter film 95a
covers the through hole 106 which is, among the through holes 102,
104, and 106 formed in the passage unit 9, the one most distant
from the longitudinal end of the passage unit 9 in a plan view.
That is, the through hole 106, which is most adjacent to the
actuator unit 21 and therefore most easy for ink adhering to the
ink ejection face 9b to enter, can be covered. This can prevent ink
from going into a region between the passage unit 9 and the ink
supply block 15 where the actuator units 21 are disposed.
In the ink-jet head 1 of this embodiment, the ink supply block 15
has the opposing face 15b facing toward the same direction as the
bond faces 90a to 90d are while being spaced apart from the support
face 9a, so that the opposing face 15b is opposed to the actuator
units 21 with respect to a direction perpendicular to the ink
ejection face 9b. This enables the ink supply block 15 to be
disposed also in a region opposed to the actuator units 21. An
amount of ink stored in the ink supply block 15 can be increased
accordingly, and therefore insufficient ink supply to the passage
unit 9 hardly occurs.
In the above-described embodiment, the lower openings of the
through holes 84 formed in the ink supply block 15 and the upper
openings of the through holes 106 formed in the passage unit 9 are
covered with the regions of the filter films 95a other than the
filter regions 96. However, this is not limitative. For example, it
may also be possible that either one of the through hole 84 and the
through hole 106 is covered with the filter films 95a. Here, it is
preferable that, in a case where the through hole 106 alone is
covered with the filter films 95a and the through hole 84 is not
covered with the filter film 95a, the through hole 84 locates on a
side opposite to the through holes 102 and 104 with respect to the
through hole 106. Thereby, even if ink adhering to the ink ejection
face 9b reaches the support face 9a through the through holes 102
and 104, the ink hardly goes further into the through hole 84 to
reach the ink inlet face 15a. In addition, the through holes 102,
104, 106, and 84 may not necessarily be covered with the filter
film 95a, as long as the filter film 95a blocks communication
between the through hole 84 and the through holes 102, 104, and
106.
In the above-described embodiment, many filter holes 96a are formed
only in the region of the filter film 95a opposed to the inflow
opening 101. However, it may not be necessary that the filter holes
96a are formed in an entire region of the filter film 95a. Even in
a case where the filter holes 96a are formed in the entire region
of the filter film 95a, by using an adhesive for fixing the filter
film 95a to the support face 9a of the passage unit 9 and for
fixing the filter film 95a to the bond face 90a to 90d of the ink
supply block 15, filter holes 96a formed in a region not opposed to
the inflow opening 101 can be filled with the adhesive. Therefore,
communication between the through holes 102, 104, and 106 and the
through hole 84 can be blocked by the filter film 95a.
In the above-described embodiment, the through holes 84 formed in
the ink supply block 15 are, in a plan view, at positions different
from positions of the through holes 104 and 106 formed in the
passage unit 9. However, the through holes 84 and the through holes
104 or 106 may be at the same position in a plan view, as long as
the filter films 95a are disposed between them.
In the above-described embodiment, the passage unit 9 and the ink
supply block 15 have elongated shapes in a plan view, and the
through holes 102, 104, 106, and 84 are formed at the both
longitudinal end portions of the passage unit 9 and the ink supply
block 15. However, this is not limitative. A shape of the passage
unit 9 and a shape of the ink supply block 15 are not limited to an
elongated one.
While this invention has been described in conjunction with the
specific embodiments outlined above, it is evident that many
alternatives, modifications and variations will be apparent to
those skilled in the art. Accordingly, the preferred embodiments of
the invention as set forth above are intended to be illustrative,
not limiting. Various changes may be made without departing from
the spirit and scope of the invention as defined in the following
claims.
* * * * *